Urine Formation Tubular Reabsorption & Secretion (PART II) Flashcards
Actions of ALDOSTERONE on LATE distal, cortical and medullary collecting tubules
- Increases ___ reabsorption - principal cells
- Increases ____ secretion - principal cells
- Increases___ secretion - intercalated cells
Na+
K+
H+
ABNORMAL Aldosterone Production
_______ _________ (Primary aldosteronism Conn’s syndrome) - Na+ RETENTION, hypokalemia, alkalosis, hypertension.
________ _____________- Addison’s disease
Na+ WASTING, hyperkalemia, hypotension
Excess aldosterone
Aldosterone deficiency
Control of Aldosterone Secretion
- Factors that __________ aldosterone secretion
• Angiotensin II
• Increased K+
• adrenocorticotrophic hormone (ACTH) (permissive role) - Factors that __________aldosterone secretion
• Atrial natriuretic factor (ANF)
• Increased Na+ concentration (osmolality)
increase
decrease
Angiotensin II— INCREASES Na+ and Water Reabsorption
- Stimulates ____________ secretion
- Directly ___________ Na+ reabsorption (proximal, loop, distal, collecting tubules)
- ___________ efferent arterioles
- decreases peritubular capillary hydrostatic pressure
- increases filtration fraction, which increases peritubular colloid osmotic pressure)
aldosterone
increases
Constricts
Angiotensin II _______ renal tubular sodium reabsorption
increases
Ang II constriction of efferent arterioles causes Na+ and
water retention and ________ excretion of waste products.
maintains
Angiotensin II BLOCKADE decreases Na+ reabsorption and blood pressure
- ACE inhibitors (captopril, benazipril, ramipril)
- Ang II antagonists (losartan, candesartin, irbesartan)
- Renin inhibitors (aliskirin)
a. ______ aldosterone
b. directly inhibit Na+ reabsorption
c. decrease_________ arteriolar resistance
decrease
efferent
Natriuresis and Diuresis = a _________ in Blood Pressure
DECREASE
Antidiuretic Hormone (ADH)
• _________ H2O permeability and reabsorption in
distal and collecting tubules
• Allows differential control of H2O and solute ______
• Important controller of extracellular fluid osmolarity
• Secreted by __________ pituitary
Increases
excretion
posterior
.ADH synthesis in the magnocellular neurons of hypothalamus, released by the posterior pituitary, and create action on the ________
kidneys
Abnormalities of ADH x 2
- Inappropriate ADH syndrome (excess ADH)
- _____________ plasma osmolarity, hyponatremia - “____________” Diabetes insipidus (insufficient ADH)
- increased plasma osmolarity, hypernatremia, excess thirst
decreased
Central
Atrial natriuretic peptide increases Na+ EXCRETION
- Secreted by cardiac atria in response to stretch (increased blood volume)
- Directly _________ Na+ reabsorption
- Inhibits ______ release and aldosterone formation
- Increases ____
- Helps to minimize blood volume expansion
inhibits
renin
GFR
Parathyroid hormone INCREASES renal Ca++reabsorption
Released by parathyroids in response to
DECREASED extracellular Ca++
- Increases Ca++ reabsorption by ________
- Increases Ca++ reabsorption by _______
- Decreases _____________ reabsorption
- Helps to increase extracellular Ca++
kidneys
gut
phosphate
Sympathetic nervous system increases Na+ reabsorption
• Directly stimulates Na+ reabsorption
• Stimulates _______ release
• Decreases ___and _____ blood flow
(only at high levels of sympathetic stimulation)
renin
GFR
renal
Increased Arterial Pressure DECREASES Na+ Reabsorption (Pressure Natriuresis)
• Increased peritubular capillary hydrostatic pressure
• Decreased _____ and __________
• Increased release of intrarenal natriuretic factors
- prostaglandins
- EDRF
renin
aldosterone
Osmotic Effects on Reabsorption
- Water is reabsorbed only by _________
- Increasing the amount of unreabsorbed solutes in the tubules _____________ water reabsorption
i.e., diabetes mellitus: unreabsorbed _________ in
tubules causes diuresis and water loss
i.e., osmotic diuretics (mannitol)
osmosis
decreases
glucose
ABNORMAL Tubular Function: INCREASED Reabsorption
- _________ Syndrome: primary aldosterone EXCESS
- Glucocorticoid Remediable Aldosteronism (GRA) EXCESS aldosterone secretion due to abnormal control of aldosterone synthase by ACTH (GENETIC)
- ________ secreting tumor: excess Ang II formation
- Inappropriate ADH syndrome: EXCESS ADH
- __________ Syndrome: excess activity of amiloride sensitive Na+ channel (genetic)
Conn’s
Renin
Liddle’s
***Liddle’s Syndrome: Excess Activity of Amiloride
Sensitive Na+Channel in Late Distal and Cortical Collecting Tubules.
Abnormal Tubular Function: DECREASED Reabsorption X 6
- _______ Insipidus: DECREASED water reabsorption, hypernatremia
- nephrogenic
- lack of ADH - ________disease: DECREASED Na+ reabsorption and DECREASED K+ secretion; lack of aldosterone
- _________ Syndrome: DECREASED Na+, Ca++, HCO3
- reabsorption, hypotension; DECREASED activity of Na-K-2 Cl TRANSPORTER in THICK loop of Henle - _________ Syndrome: DECREASED NaCl reabsorption, hypotension; DECREASED activity of NaCl co-transporter in distal tubule (genetic)
Diabetes
Addison’s
Bartter’s
***Bartter’s Syndrome: Decreased Activity of Na-K-2Cl
Co-Transporter in THICK Ascending Loop of Henle
Gitleman’s
Abnormal Tubular Function: DECREASED Reabsorption X 6
- ______ syndrome: generalized decrease in reabsorption often in proximal tubules; causes: genetic, HEAVY METAL damage, DRUGS (tetracyclines), multiple myeloma, tubular necrosis (ischemia)
- _____tubular acidosis: DECREASED H+ secretion,
Increased HCO3
- excretion, acidosis causes: genetic, renal injury, etc.
Fanconi
Renal
Bartter’s Syndrome: DECREASED Activity of Na-K-2Cl
Co-Transporter in THICK Ascending Loop of Henle
Treatment: high NaCl, K+intakes, ______ blockers (e.g. aspirin)
prostaglandin
Gitleman’s Syndrome: DECREASED NaCl Reabsorption in ______ Distal Tubule
Treatment: high NaCl and K+ intakes, Mg++ supplements
Early
_________ secretion – the movement of substances out of the blood and into the tubular fluid; the reverse of
reabsorption.
Descending limb of the loop of Henle secretes _____
through diffusion
_________and collecting tubules secrete potssium,
hydrogen, and ammonium ions
Tubular
urea
Distal
Tubular Secretion X 6
Important for:
- Disposing of substances not already in the filtrate,
such as certain _________ - Eliminating undesirable substances or end products
that have been _________ by passive processes
(urea and uric acid) - Ridding the body of excess _____
- Controlling blood pH
- _________ – hormone that targets the cells of the
distal and collecting tubule cells causing increased
activity of the Na-K pumps - _________of hydrogen ions increases with increased blood hydrogen ion concentration
drugs
reabsorbed
K+
Aldosterone
Secretion
Urine Composition X 7
• Approximately______ water
• ______ _________ – result of protein metabolism;
e.g., urea, uric acid, ammonia, and creatinine
•___________ – Na, K, NH4, Cl, HCO3, PO4, and SO4
• Toxins
• Pigments – urochromes
• Hormones – high hormone levels may spill into the
filtrate
• Abnormal constituents – such as blood, glucose,
albumin, casts, or calculi
95%
Nitrogenous wastes
Electrolytes
